DESC SMD No. 5962-86063
鈥?/div>
Standard EPROM Pinout
GENERAL DESCRIPTION
The WS57C256F is a High Performance 256K UV Erasable Electrically Programmable Read Only Memory. It is
manufactured using an advanced CMOS process technology enabling it to operate at speeds as fast as 55 ns
Access Time.
Two major features of the WS57C256F are its Low Power and High Speed. While operating in a TTL environment it
consumes less than 120 mA while cycling at full speed. Additionally, the WS57C256F can be placed in a standby
mode which drops operating current below 5 mA in a TTL environment and 500 碌A(chǔ) in a CMOS environment.
The WS57C256F also has exceptional output drive capability. It can source 4 mA and sink 16 mA per output.
The WS57C256F is configured in the standard EPROM pinout which provides an easy upgrade path for systems
which are currently using standard EPROMs.
MODE SELECTION
PINS
MODE
Read
Output
Disable
Standby
Program
Program
Verify
Program
Inhibit
Signature
3
CE/
PGM
VIL
X
VIH
VIL
X
VIH
VIL
VIL
OE
VIL
VIH
X
VIH
VIL
VIH
VIL
VIL
A9
X
X
X
X
X
X
A0
X
X
X
X
X
X
VPP VCC OUTPUTS
VCC VCC
VCC VCC
VCC VCC
VPP
2
VCC
VPP
2
VCC
VPP
2
VCC
DOUT
High Z
High Z
DIN
DOUT
High Z
23 H
4
5
PIN CONFIGURATION
TOP VIEW
Chip Carrier
A
7
A
12
V
PP
NC
V
CC
A
14
A
13
V
PP
A
12
A
7
A
6
A
5
A
4
A
3
A
2
A
1
A
0
O
0
O
1
O
2
GND
CERDIP
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
V
CC
A14
A13
A8
A9
A11
OE
A10
CE/PGM
O
7
O
6
O
5
O
4
O
3
VH
2
VIL VCC VCC
VH
2
VIH VCC VCC
A
6
A
5
A
4
A
3
A
2
A
1
A
0
NC
O
0
4 3 2
32 31 30
1
5
29
6
28
7
27
8
26
9
25
10
24
11
23
12
22
13
21
14 15 16 17 18 19 20
O
1
O
2
GND
A
8
A
9
A
11
NC
OE
A
10
CE/PGM
O
7
O
6
EO H
NC O
3
O
4
O
5
NOTES:
1. X can be V
IL
or V
IH
.
2. V
IH
= V
PP
= 12.75 鹵 0.25 V.
3. A1 鈥?A8, A10 鈥?A14 = V
IL
.
4. Manufacturer Signature.
5. Device Signature.
PRODUCT SELECTION GUIDE
PARAMETER
Address Access Time (Max)
Output Enable Time (Max)
WS57C256F-55
55 ns
25 ns
WS57C256F-70
70 ns
30 ns
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STMICROELECTRONICS
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